The US Southern Command has launched an investigation into "credible allegations" that guards at Guantanamo Bay abused detainees, and has appointed an army colonel to head the probe.

The Pentagon's Inspector General's office said that it had ordered the Miami-based Southern Command to investigate after Marine Lt Col Colby Vokey, who represents a detainee at the US naval base in eastern Cuba, filed the "hotline" complaint last week.

Col Vokey attached a sworn statement from his paralegal, Sgt Heather Cerveny, 23, in which she said several guards in a bar at Guantanamo Bay bragged about beating detainees and described it as common practice. "Others were talking about how when they get annoyed with the detainees, about how they hit them, or they punched them in the face," Sgt Cerveny said during a telephone interview Thursday.

"It was a general consensus that I [detected] that as a group this is something they did. That this was OK at Guantanamo, this is how the detainees get treated."

Sgt Cerveny visited the US naval base in Cuba last month and said she spent an hour with the guards at the military club. The guards stopped discussing beating detainees after finding out she works for a detainee's legal team.

In her complaint, she wrote: "From the whole conversation, I understood that striking detainees was a common practice... Everyone in the group laughed at the others' stories of beating detainees."

Asked on Thursday if the conversation could have been exaggerated bar talk, she said: "I don't think that they were trying to impress me in any way. They were already in a discussion in there when I walked into a group."

She said she filed the complaint because "I don't think it's right for us to be allowing these prisoners to be treated poorly... I think we should hold ourselves to a higher standard."

Gary Comerford, spokesman for the Pentagon's Inspector General's office, said that in the past two days, the case "has been referred to Southcom for action. They're going to have to look into this."

General John Craddock, the commander of Southern Command, said later that he had ordered the investigation, headed by an army colonel, to begin. "The investigation is consistent with US Southern Command's policy to investigate credible allegations of abuse at Guantanamo detention facilities," the Southern Command said in a statement.

The military Joint Task Force that runs the detention camps in Guantanamo Bay promised to work with investigators from the Southern Command, which oversees US military operations in the Caribbean and Latin America.
"The Joint Task Force will co-operate fully with Southcom to learn the facts of the matter and will take action where misconduct is discovered," said Navy Commander Rob Durand, spokesman for the detention centre, from the base.

He insisted that his group's mission "is the safe and humane care and custody of detained enemy combatants. Abuse or harassment of detainees in any form is not condoned or tolerated."

The Inspector General receives 14,000 tip-offs on misconduct each year via the hotline, and opens 3,000 cases as a result, Commander Comerford said. There are now 454 detainees at Guantanamo Bay, according to Vincent Lusser, a spokesman for the Geneva-based International Committee of the Red Cross.

The Red Cross has recently completed a two-week visit to the prison, meeting the alleged mastermind of the 9/11 attacks and 13 other high-profile detainees who were transferred there weeks ago from CIA custody. The encounters apparently mark the first time the 14 detainees have spoken to anyone other than their captors since they were arrested. They had been held in CIA custody at secret locations and were transferred weeks ago to the Guantanamo Bay Naval Base in Cuba.

The men include Khalid Sheikh Mohammed, who allegedly planned the 11 September 2001 attacks on New York and Washington. He was believed to be the No 3 al-Qa'ida leader before he was captured in Pakistan in 2003. Also among the 14 new detainees are Ramzi Binalshibh, who is accused of helping to plan the 9/11 attacks and being a lead operative for a foiled plot to crash aircraft into Heathrow Airport; and Abu Zubaydah, who was believed to be a link between Osama bin Laden and others in al-Qa'ida.

The Red Cross had been trying to obtain access to US detainees in secret locations for a long time, Mr Lusser said. Red Cross officials said they are supposed to have access to all prisoners of war and were aware of the arrests of some detainees in recent years, but were unable to find them in the US detention facilities they visited.

Until the 14 detainees were recently transferred to Guantanamo Bay, their whereabouts were unknown. The locations of the CIA prisons remain secret.

Mr Lusser said there were now 454 detainees at Guantanamo and that the Red Cross has private access to all of them. He said Red Cross workers in Afghanistan regularly visit the 600 detainees at the US military prison at Bagram air base.